Distinguish a claim backed by real, checkable evidence from a bare assertion that only sounds convincing.
Persuasive writing sometimes states things with total confidence and backs them up with nothing at all. This is called a bare assertion -- a claim dressed up to sound like a fact, with no evidence actually attached. Confidence in the writing is not proof of anything; a sentence can sound absolutely certain and still be completely unsupported.
One reliable tell is the phrase "everyone knows" or "obviously" showing up right before a claim -- these phrases often do the persuading that evidence should be doing instead. Learning to notice the gap between a confident tone and an actual fact is one of the most useful reading habits for evaluating anything you read online or anywhere else.
Mastery looks like: They can identify a bare assertion by name, explain what specific evidence is missing, and can convert one into a properly supported claim.
Common stumbles: Assuming a confidently worded claim must be well-supported, without checking whether any actual checkable evidence is attached to it.